1. Field of the Invention
The present invention relates to disk drives for computer systems. More particularly, the present invention relates to a disk drive executing a preemptive multitasking operating system comprising tasks of varying priority.
2. Description of the Prior Art
Prior art disk drives have been implemented by distributing the operating tasks among multiple hardware components to alleviate the bandwidth of a single microprocessor. For example, the disk drive may comprise a disk controller for interfacing with the host, performing cache operations and background operations, etc., and a servo controller for performing the real-time servo control operations of the voice coil motor and spindle motor. However, a distributed architecture increases the cost of the disk drive due to the number of hardware components needed to perform each designated task.
In addition, prior art disk drives may execute a cooperative multitasking operating system comprising only two tasks: a disk task for performing disk related operations and background operations (e.g., diagnostic procedures), and a host task for interfacing with a host computer. Because the background operations are implemented by the disk task they cannot be easily interrupted when a new host command is received.